With your favorite editor, put these lines into admin/sql/updates/mysql/0.0.13.sql:

admin/sql/updates/mysql/0.0.13.sql

ALTERTABLE`#__helloworld`ADD`params` VARCHAR(1024)NOTNULLDEFAULT'';

The TableHelloWorld has to be modified in order to deal with these parameters: they will be stored in a JSON format and get in a JParameter class. We have to overload the bind and the load method. With your favorite editor, put these lines into admin/tables/helloworld.php

Adding some translation strings

Some strings have to be added in the admin/language/en-GB/en-GB.com_helloworld.ini file

admin/language/en-GB/en-GB.com_helloworld.ini

# Joomla16.Tutorials
# Copyright (C)2005 - 2009 Open Source Matters. All rights reserved.
# License GNU General Public License version 2 or later; see LICENSE.txt, see LICENSE.php
# Note : All ini files need to be saved as UTF-8 - No BOM
COM_HELLOWORLD_ADMINISTRATION=HelloWorld administrationCOM_HELLOWORLD_CATEGORIES=CategoriesCOM_HELLOWORLD_MANAGER=HelloWorld managerCOM_HELLOWORLD_MESSAGES=MessagesCOM_HELLOWORLD_HELLOWORLD_CATEGORY=CategoryCOM_HELLOWORLD_HELLOWORLD_CATEGORY_DESC=Category of the messageCOM_HELLOWORLD_HELLOWORLD_CREATING=CreatingCOM_HELLOWORLD_HELLOWORLD_DETAILS=DetailsCOM_HELLOWORLD_HELLOWORLD_OPTIONS=OptionsCOM_HELLOWORLD_HELLOWORLD_EDITING=EditingCOM_HELLOWORLD_HELLOWORLD_ERROR_SOME_VALUES_ARE_UNACCEPTABLE=Some values are unacceptableCOM_HELLOWORLD_HELLOWORLD_GREETING_DESC=Message to be displayedCOM_HELLOWORLD_HELLOWORLD_GREETING=GreetingCOM_HELLOWORLD_HELLOWORLDLIST_ARE_YOU_SURE_YOU_WANT_TO_DELETE_THESE_GREETINGS=Are you sure you want to delete these greetings?COM_HELLOWORLD_HELLOWORLDLIST_GREETING=GreetingCOM_HELLOWORLD_HELLOWORLDLIST_GREETINGS_REMOVED=Greetings removedCOM_HELLOWORLD_HELLOWORLDLIST_ID=IdCOM_HELLOWORLD_HELLOWORLDLIST_ONE_OR_MORE_GREETINGS_COULD_NOT_BE_DELETED=One or more greetings could not be deleted: %sCOM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_MSG_DESC=This message will be displayedCOM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_MSG_LABEL=MessageCOM_HELLOWORLD_CONFIGURATION=ConfigurationCOM_HELLOWORLD_CONFIG_GREETING_SETTINGS_LABEL=Greeting settingsCOM_HELLOWORLD_CONFIG_GREETING_SETTINGS_DESC=Greetings settings descriptionCOM_HELLOWORLD_PARAMS_SHOW_CATEGORY_LABEL=Show categoryCOM_HELLOWORLD_PARAMS_SHOW_CATEGORY_DESC=Display the category after the message

Create a compressed file of this directory or directly download the archive and install it using the extension manager of Joomla!1.6. You can add a menu item of this component using the menu manager in the backend.